public String getIpAddr(HttpServletRequest request) { 
     String ip = request.getHeader("x-forwarded-for"); 
     if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
         ip = request.getHeader("Proxy-Client-IP"); 
     } 
     if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
         ip = request.getHeader("WL-Proxy-Client-IP"); 
     } 
     if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
         ip = request.getRemoteAddr(); 
     }      
//返回一串ip值的话,取第一个     if(ip.contains(",")){
      ip = ip.substring(0, ip.indexOf(","));
     }
     return ip; 
 }